1. Field of the Invention:
This invention relates, in general, to heat exchangers and, more specifically, to radiator assemblies for fluid-filled electrical apparatus.
2. Description of the Prior Art:
Radiator assemblies for fluid-filled electrical apparatus have been constructed in many different shapes and arrangements. Some of the most efficient arrangements use sheet metal panels which are formed and welded together to provide ducts through which the liquid coolant flows. Several of these two-panel combinations, or radiator sections, are joined together in fluid communication by header assemblies which are connected to the electrical apparatus enclosure.
One widely-used prior art radiator arrangement uses a plurality of radiator sections, each with openings at their top and bottom ends, which, when connected to a simple header assembly, permit the flow of coolant through ducts in the radiator sections. A considerable number of welded or brazed joints are necessary on each section to form a liquid-tight seal with each header assembly. These joints require a considerable amount of labor expense and are regarded as possible locations of failure and fluid leakage. However, the solid tube or pipe used to form each header assembly provides sufficient cantilever strength to support the radiator assembly and the coolant contained therein.
Another common type of radiator assembly uses a so-called "integral header" construction. As shown in U.S. Pat. Nos. 4,019,572; 3,650,312; 3,506,064; 1,999,246; and 1,619,334, the radiator assembly includes a plurality of radiator sections which are connected together by flanges extending from the metal panels which form each radiator section. The flanges are formed into these panels and are dimensioned to allow the flanges to telescope together to form a header for the radiator assembly. Although the integral header construction simplifies assembly of the radiators and provides a reliable fluid-tight joint, additional support and bracing is necessary to support the weight of the radiator assembly and coolant because thin sheet metal is used to form the metal panels. In addition, the severe forces encountered during shipping of such apparatus prohibit integral header radiator assemblies from being shipped in place on the tank wall, thereby necessitating their removal after final testing. Besides additional bracing and support, integral headers still require considerable labor since all of the external welds must be done manually because automatic welding equipment cannot pass through the space between radiator sections.
Thus, it would be desirable to provide a radiator assembly for fluid-filled electrical apparatus having a construction that permits automatic joining equipment to be used in assembling the header and radiator sections. It would also be desirable to provide a radiator assembly having a header construction that provides sufficient support so that additional bracing of the radiator assembly is not required, and would, also, enable the radiator assembly to be mounted and shipped in place on the tank of the electrical apparatus.